(1) Field of the Invention
The present invention relates to a remote control method and a unit for a radio unit, which execute remote control of a transmission power or the like, and in particular, to a remote control method and a unit for a radio unit including a supervisory control unit which is located in the vicinity of the radio unit, and monitors and controls an operating state of the radio unit, and a remote control unit which is connected to the supervisory control unit through a communication control line, and being controlled by means of the remote control unit through the supervisory control unit.
(2) Description of the Related Art
There is a radio unit which is divided into an outdoor unit located together with an antenna to avoid having a waveguide lengthened, and an indoor unit connected to the outdoor unit by means of a coaxial cable. According to such a radio unit, a remote control unit, which is located on the outdoor unit, controls a transmission power or the like of the outdoor unit.
As shown in FIG. 1, a conventional radio unit comprises an outdoor unit (referred to as "ODU" (Out-Door unit) hereinafter) 60, and an indoor unit (referred to as "IDU" (In-Door Unit) hereinafter) 65. The ODU 60 is composed of an ODU communication device 61, and an ODU-SV (Supervisor) section 62 which monitors and controls the ODU communication device 61. On the other hand, the IDU 65 is composed of an IDU communication device 66, and an IDU-SV (Supervisor) section 67 which monitors and controls the IDU communication device 66, and controls the ODU communication device 61 via the ODU-SV section 62.
The IDU communication device 66 comprises a DPU (Digital Processor Unit) 66a which executes an interface signal processing with low-order devices for frame synchronization, multiplex/separate or the like, a MODEM 66b which executes modulation/demodulation, and an IF section 66c which amplifies an intermediate frequency. The ODU communication device 61 comprises an IF section 61a which amplifies an intermediate frequency, and a RF section 61b which amplifies a high frequency. The IF sections 66c and 61a are connected to each other by means of main signal communication lines 71a and 71b composed of a coaxial cable, and transmission and reception signals are transmitted therethrough. The RF section 61b is connected to an antenna 70, and microwaves are transmitted and received between this antenna 70 and another base station.
The ODU-SV section 62 is composed of a supervisory control section 62a which monitors a voltage of each section of the ODU communication device 61, occurrence of an alarm, a reception power, and executes a transmission power control, and a communication control section 62b which controls the communication between the supervisory control section 62a and the IDU-SV section 67. The IDU-SV section 67 is composed of a supervisory control section 67a which monitors and controls the IDU communication device 66, and the 0DU communication device 61 through the supervisory control section 62a, and a communication control section 67b which controls the communication between the supervisory control sections 67a and 62a. These communication control sections 62b and 67b are connected by means of communication control lines 72a and 72b, and a serial signal is transmitted and received between both.
In the case where there is a failure such that a serial signal is not transmitted from the communication control section 67b of the IDU-SV section 67, it seems that the cause results in disconnection of the communication control line 72b, or in a failure occurring in the ODU-SV section 62. However, according to a conventional radio unit, it is impossible to make a decision which failure occurs in the IDU 65.
In order to specify a portion where a failure occurs, it is required to actually go to an antenna located at a high place, and to check the ODU-SV section 62. For this reason, the cause of failure can not be quickly found and removed, and there is the possibility of causing a lowering of communication service and an enlargement of the failure.